A crowd of supporters cheer as Pope Francis arrives at Andrews Air Force Base, just outside of Washington, DC.

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The pope was greeted by President Barack Obama and First Lady Michelle Obama, as well as by other political and Catholic leaders.

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President Obama shakes hands with Pope Francis during the arrival ceremony at the White House on Wednesday.

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Here, they stand for the national anthem.

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President Obama and Pope Francis wave to the crowd, which was so large that it stretched back around the Ellipse and onto the National Mall.

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After the ceremony, Pope Francis arrived for the Midday Prayer of the Divine at the Cathedral of St. Matthew the Apostle. More than 300 US Bishops were in attendance..

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A nun reaches out to touch Pope Francis as he arrives at the Basilica of the National Shrine of the Immaculate Conception for a Canonization Mass for Friar Junipero Serra.

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Pope Francis delivered a powerful speech during a joint meeting of the US Congress Thursday.

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During his speech, the pope addressed the topics of immigration, global warming, prison reform, the arms trade, wealth inequality, and the role of money in the political system.

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People even gathered on the West Lawn of the US Capitol to watch the pontiff's speech by video screen.

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Here, he blesses a young child.

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After his speech, Pope Francis stepped outside to greet the crowd that had gathered.

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After a successful DC visit, the pope was off to New York City.

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At New York's John F. Kennedy Airport, the pope was greeted by followers and gifted a small replica doll.

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He engaged with the crowd, giving well wishes to Gerard Gubatan of Brooklyn (center left).

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He then hopped in a helicopter to get into the city.

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Here, he rides in the famous "popemobile" outside of St. Patrick's Cathedral in New York City.

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Pope Francis shares a reflection during a prayer service at St. Patrick's Cathedral that evening.

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On Friday, Pope Francis arrived at the General Assembly of the United Nations, where he repeated his concern on behalf of the global poor.

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"They are cast off by society, forced to live off what is discarded, and suffer unjustly from the consequences of abuse of the environment. These phenomena are part of today's widespread and quietly growing 'culture of waste,'" he said.

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Next, he was off to the interdenominational service at the site of the 9/11 memorial and museum.